This work is an account of investigations into the chemistry of members of the Amaryllidaceae and Hyacinthaceae families. The plants of the family Amaryllidaceae are a large group comprising over sixty genera and more than a thousand species. They are widely distributed, but are found more richly in the tropics, with a particularly high density in South Africa, with smaller centers of diversity in Andean South America and the Mediterranean. Amaryllidaceae plants have been extensively used by local traditional healers and have been reported to have numerous pharmacological uses. The alkaloids isolated from this family are a group of isoquinoline alkaloids found exclusively in this family. Plants belonging to two Amaryllidaceae genera were investigated phytochemically, one from each of the sub-tribes Crinineae and Amaryllidineae were investigated phytochemically. Brunsvigia natalensis is used in local traditional medicine to "straighten bones of children", treat barrenness in women and ease childbirth. This is the first phytochemical investigation of Brunsvigia natalensis, and yielded two new alkaloids, a new ceramide type compound and a known flavanoid. A comparative phytochemical investigation was carried out on the bulbs and seeds of Crinum stuhlmanni, which resulted in a number of different alkaloids being isolated from the seeds and bulbs of this plant. The southern African Hyacinthaceae is a large and chemically morphologically diverse group of plants. This family comprises approximately sixty-seven genera and nine hundred species worldwide, of which twenty-seven genera and three hundred and sixty - eight species are found locally. There are five sub-families of which three occur in southern Africa. The chemical constituents of this family can be divided into four classes, namely homoisoflavanones, steroidal compounds, bufadienolides and miscellaneous compounds. These plants are used in local traditional medicine for treating ailments such as hangovers, rheumatic fever, sprains and even cancer. The phytochemistry of three Hyacinthaceae plants was studied. The phytochemical investigation of Drimia macrocentra and Urginea riparia yielded a novel bufadienolide glycoside. These glycosides are quite unusual with the glycone attached to the aglycone at C-2 and C-3 and this has only been reported only once before in this family. The phytochemical investigation of Ledebouria revoluta yielded a number of homoisoflavanones. These homoisoflavanones have been shown to have anti-inflammatory activity and all of the compounds isolated in this work have been screened for this activity. Structural elucidation was carried out using spectroscopic methods such as NMR, MS, UV and IR. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2004.

There is a resurgence of interest in many countries in medicinal plants and their curative properties (HARBORNE & BAXTER, 1993). Little work has previously been conducted on the Sterculiaceae species, especially those located within South Africa. This was a perfect opportunity to broaden the available information on the medicinal properties and chemical constituents of this family, within KwaZulu-Natal. Of the 50 genera of the Sterculiaceae family, six are located in South Africa: Cola, Oombeya, Hermannia, Melhania, Sterculia and Waltheria . Seven Sterculiaceae species were chosen for investigation. They varied in growth type and use in traditional medicine. These species included: Oombeya rotundifolia, D. burgessiae, D. cymosa, Cola natalensis, C. greenwayi, Hermannia depressa and Sterculia murex. Plant material used in the study was collected from a variety of areas, all within KwaZulu-Natal or the Northern Province. There were two collection sites for D. rotundifolia, from differing habitats, and results were compared. The material was screened pharmacologically for anti-bacterial activity using the disc-diffusion assay and Minimal Inhibitory Assay (MIC), and for antiinflammatory activity using the COX-1 assay. Only D. rotundifolia and C. natalensis were tested for anti-bacterial activity using the disc-diffusion assay as the disc-diffusion asay was found to show inconsistencies in the results obtained. Bacteria used included: Escherichia coli and Klebsiella pneumoniae being Gram-negative, and Micrococcus luteus, Staphylococcus aureus and Staphylococcus epidermidis being Gram-positive. D. rotundifolia exhibited activity, both anti-bacterial and bacteriostatic, in the leaf, twig and bark extracts from both collection sites. Only the water extract obtained from the leaf material of C.natalensis exhibited slight anti-bacterial activity against S. epidermidis. Minimal inhibitory concentration (MIC) values were determined using a microdilution assay (25 mg ml-1 serially diluted 50 % to 0.195 mg ml-1). Bacteria used in the screening were: B. subtilis, E. coli, K. pneumoniae and S. aureus. None of the water extracts showed any antibacterial activity. Good MIC values were exhibited by D. cymosa ethanolic leaf extracts, C. greenwayi leaf ethyl acetate extracts especially against K. pneumoniae (0.78 mg ml-1) and S. aureus (0.39 mg rnl-1) and H. depressa ethanol and ethyl acetate leaf, stem and root extracts. D. burgessiae and S. murex showed low activity, with insignificant MIC values. D. rotundifolia plant material yielded the highest anti-inflammatory activity of all the plant species, with the extracts from the Umgeni Valley Nature Reserve(UVNR) showing the best results. The lowest activity was recorded in the aqueous bark extracts (5% inhibition)and the highest from the ethanolic leaf extract (97% inhibition). D. cymosa extracts showed high activity in ethanolic leaf and twig extracts with low activity in all the other extracts. D. burgessiae, C. greenwayi and S. murex extracts showed high activity in both ethanolic and dichloromethane extracts from leaf and twig material. Activity occurred in the dichloromethane extracts of H. depressa obtained from the stem (78%) and root (81%) extracts. C. natalensis extracts showed insignificant activity. Plant material was phytochemically screened for alkaloids, saponins, tannins, cardiac glycosides and cyanogenic glycosides. No alkaloids were detected using pH-partitioning and no cyanogenic glycosides were observed (TLC sandwich method) in any of the extracts of the seven species screened. Using the gelatin salt-block test, tannins were found to be present in the leaf and twig material of D. rotundifolia, the leaf material of C. greenwayi and the leaf, stem and root material of H depressa. The froth test indicated that saponins were present in the leaf and twig material of D. rotundifolia and leaf, root and stem material of H. depressa. The haemolysis test indicated the presence of saponins in the D. rotundifolia bark material. Screening for cardiac glycosides detected cardienolides in the leaf, twig and bark material of D. rotundifolia, and bufadienolides were detected in D. rotundifolia , D. cymosa, D. burgessiae and S. murex. Five species screened were selected for isolation of active anti-bacterial compounds: D. rotundifolia, D. burgessiae, D. cymosa, C. greenwayi and H. depressa. Material was extracted by Soxhlet and isolation techniques employed were VLC, TLC separation, Sephadex LH-20 column chromatography and HPLC techniques. The isolated compounds were analysed by NMR and GCMS. All isolated compounds were fatty acids: Palmitic acid, Myristic acid, Lauric acid, Stearic acid, Acetic acid as welll as stearyl alcohol, eicosane and octadecane. The aqueous eaf extract of H. Depressa exuded a thick mucilage. The production of this mucilage from the H. depressa aqueous extract may have medicinal or commercial value. A technique to separate the mucilaginous extract from the leaf material was devised. After extraction, the extract was screened to determine its sugar content through gas chromatography. It was screened for its pharmacological properties: antibacterial and anti-inflammatory activity. The hydrolysing effect of -amylase and HCI on the extract was determined to find its potential use as a bulking agent for use as an appetite suppressant, laxative or against the effects of diarrhoea. It was concluded that the extract is not likely to break down easily in the human digestive system and may be effective against the three listed ailments . / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2002.

The phytochemistry of Ochna serrulata (Hochst.) Walp. was investigated for the first time; two new dimeric chalcones (5-deoxyurundeuvine C and serrulone A) and two new biflavonoid derivatives (4,4’,7-tri-O-methylisocampylospermone A and 4”’-de-Omethylafzelone A) were isolated. These compounds were isolated along with the known compounds lophirone A, afzelone B, campylospermone A, isocampylospermone A, ochnaflavone, 2”,3”-dihydroochnaflavone, lophirone C, psilosin, 3’-O-methylpsilosin, a cyanoglucoside, epicatechin, (2’,4’- dihydroxyphenyl)acetic acid, methyl (2’,4’-dihydroxyphenyl)acetate, irisolone 4’- methyl ether, iriskumaonin 3’-methyl ether, 3',4'-dimethoxy-6,7-methylenedioxyisoflavone, lophirone L, syringaresinol and 16α,17-dihydroxy-entkauran-19-oic acid. The growth inhibitory effect of these compounds was evaluated against three cancer cell line panel of TK 10 (renal), UACC62 (melanoma) and MCF7 (breast) using a sulforhodamine B (SRB) assay. Ochnaflavone and 3’-methoxypsilosin demonstrated selectivity and only inhibited the growth of melanoma cancer cells. However, ochnaflavone showed higher activity by totally inhibiting the growth of melanoma cancer cells at 12.91 μM, whereas, 3’-O-methylpsilosin has this effect at a concentration of 14.11 μM. Lophirone C, a dimeric chalcone, demonstrated the highest cytotoxic activity amongst all isolated compounds against renal, melanoma and breast cancer cells with TGI at 35.63 μM, 11.67 μM and 30.35 μM, respectively. Lophirone A, a rearranged biflavonoid, showed TGI against these cancer cells at 58.96 μM, 26.23 μM and 40.01 μM, respectively. The rest of the compounds showed no significant cytotoxicity against the three cancer cells. The new biflavonoid, 4,4’,7-tri-O-methylisocampylospermone A demonstrated the highest antimalarial activity against chloroquine-resistant strains of Plasmodium falciparum (FCR-3) with IC50 of 11.46 μM, followed by ochnaflavone (17.25 μM). iv Serrulone A (26.52 μM), lophirone A (29.78 μM), 5-deoxyurundeuvine C (31.07 μM), lophirone C (35.31 μM), 4”’-de-O-methylafzelone A (38.43 μM), afzelone B (39.54 μM), irisolone 4’-methyl ether (40.72 μM) and syringaresinol (42.66 μM) were moderately active. The following compounds exhibited the lowest antimalarial activity, 2”,3”-dihydroochnaflavone (61.86 μM), iriskumaonin 3’-O-methyl ether (93.69 μM),3’- O-methylpsilosin (106.35 μM) and16α,17-dihydroxy-ent-kauran-19-oic acid (106.48 μM). Owing to the observed and reported biological/pharmacological activity, ochnaflavone (an ether-linked biflavone consisting of apigenin and luteolin moieties) was selected for synthetic studies. An older method, nucleophilic aromatic substitution (SNAr) was successfully applied in the construction of the diary ether. Oxidative ring cyclization of the ether-linked dimeric chalcone was achieved by using heated pyridine and iodine. The two methods can be extended further in the synthesis of other novel biflavones with ether linkage. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2003.

No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2003.

Plants have formed the foundation of traditional medicine systems throughout the world for thousands of years and continue to provide mankind with new remedies for various ailments. A large portion of the black South African population still depends on medicinal plants as primary health care due to its affordability, accessibility and cultural importance. These medicinal plants need to be investigated since new lead compounds are often found in nature. Homoisoflavanones isolated from South African and Indian plants were found to exhibit anti inflammatory activities although the mechanism of action has not yet been determined. A few reports on the anti fungal activities of these compounds were also found. Four new and three known homoisoflavanones of the 3-benzylidene-4-chromanone type were synthesized and tested for anti-inflammatory and antifungal activities. Two novel intermediates were also synthesised. Enantiomers of a homoisoflavanone of the 3-benzyl-4- chromanone types were also synthesized from the corresponding 3,5-dimethoxy phenol via 4- chromanone in six steps. This is the first report of the synthesis of an enantiomerically pure homoisoflavanone compound together with its opposite isomer. The enantiomers and racemate were tested for anti-inflammatory activity. All the synthesized homoisoflavanones were screened for cytotoxicity. The structures of these homoisoflavanones were elucidated by NMR spectroscopy along with HRMS data. The crystal structure of a homoisoflavanone with anti-inflammatory and antifungal activity is reported. The anti-inflammatory activity of the homoisoflavanones was determined in an acute croton oil-induced auricular dermatitis mouse model. The antifungal activity was performed in vitro against a Candida albicans strain. Compounds were tested for cytotoxicity against a Chinese Hamster Ovarian (CHO) cell line using the 3-(4,5-dimethylthiazol-2-yl)-3,5- diphenyltetrazoliumbromide (MTT) assay. In conclusion, the synthetic homoisoflavanones showed anti-inflammatory as well as antifungal activity. Some of the compounds showed anti-inflammatory activity comparable to that of the commercially available diclofenac. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2011.

This research study undertook to investigate and evaluate for efficacy and safety, the herbal remedies used for treating Diabetes mellitus in northern KwaZulu-Natal. In addition, it sought to gain knowledge and better understanding of traditional healing systems and the medicinal use of the natural flora. During the process of assimilating the desired information, the epidemiological and socio-economic factors which determine the form of medicine chosen by rural people in the region, were quantified. Both aspects of explanatory studies i.e. experimental and observational were used. Firstly, to evaluate the safety of the two herbal remedies, laboratory animals were given an oral dose of the herbal medicine and observed for a period of 14 days. Efficacy was assessed by treating Streptozotocin-induced diabetic rats with the herbal remedies and comparing their effect on blood glucose with that of a conventional sulphonylurea. The second part of the study was observational and it involved monitoring human subjects (patients) for twelve months, who were already taking the herbal preparations (n=56) and comparing their prognoses with that of a group taking conventional medicine (n=97). A third group using both types of medicine (n=42) was included as control measure for a possible confounding factor. Main outcome measures; Both subjective and objective measures of the perceived health of the diabetic patients were measured, as well as the determinants of using traditional medicine versus conventional medicine. The battery of toxicity tests which utilises behavioural and functional observations of the laboratory animals, yielded no signs of toxicity or abnormal behaviour. The histopathological examination results of the sample organs from the treated rats also revealed no signs of abnormality that could be attributed to the herbal remedies tested. There was no sex variation recorded in the response. The first HP tested (HP-1) demonstrated minimal hypoglycaemic effect whereas HP-2 significantly lowered the blood glucose of the streptozotocin-induced diabetic rats by an average of 59%. This was comparable to the conventional medicine (Glibenclamide) used in the experiment. After 12 months of follow-up, 93 % of traditional medicine users (n=56) were convinced that their blood sugar was controlled because of the traditional remedy they were using. The proportion of diabetic cases who used conventional medicine were no better off than those who used traditional medicine or vice versa. Health status and the financial situation (income) of the respondents greatly influenced their choice for diabetic treatment. The herbal remedies that were investigated were non-toxic and safe for use and internal consumption. One preparation demonstrated a significant hypoglycaemic effect, which was comparable to the conventional allopathic medicine used in treating Diabetes mellitus. This study should serve as a springboard to encourage more pharmacological evaluation of herbal medicines. / Thesis (Ph.D.)-University of Durban-Westville, 1998.

An investigation was undertaken to determine whether Erythrina species indigenous to South Africa contained the same type of compounds as Erythrina species not found in South Africa and to determine whether they displayed any anti-inflammatory and antibacterial activity. Phytochemical analysis was conducted using thin layer chromatography. A great similarity was found in the leaf profiles of the species being studied. The leaf and bark extracts of E. caffra and E. lysistemon appear to have similar profiles when viewed under normal light and ultraviolet light, (254 and 366 nm). These two species have similar banding patterns when stained with fast blue reagent for flavonoids and potassium hydroxide reagent for coumarins. The five species that were tested appear to contain alkaloids, flavonoids, coumarins and triterpenes just like the species not found in South Africa from this genus. Dried bark and leaves from E. caffra, E. humeana, E. latissima, E. lysistemon and E. zeyheri were screened for anti-inflammatory and anti-bacterial activity. Ethanol, ethyl acetate and water extracts were screened for both anti-inflammatory and anti-bacterial activity. The cyclooxygenase bioassay was used to test for anti-inflammatory activity. The ethanol and ethyl acetate extracts generally displayed activity while the water extracts displayed no activity for both the bark and the leaves. The bark generally displayed more cyclooxygenase inhibitory activity than the leaves. The bark of E. caffra and E. lysistemon displayed the highest cyclooxygenase inhibitory activity. The disc diffussion bioassay was used to screen for anti-bacterial activity. Anti-bacterial activity was only detected in the water extracts of the leaves. The water extracts of the bark showed very little or no activity. The bark yielded more anti-bacterial activity than the leaves. Anti-bacterial activity was mainly displayed against Gram positive bacteria. The bark of E. caffra and E. lysistemon displayed the highest anti-bacterial activity. On the basis of the screening results it was decided to use bioasssay guided fractionation in an attempt to isolate putative anti-inflammatory and anti-bacterial compounds. A hexane extract from the bark of E. lysistemon was prepared and purified using a range of chromatographic methods. Vacuum liquid chromatography, separation using a chromatotron, thin layer chromatography and high performance liquid chromatography were used to isolate anti-inflammatory compound(s). The isolation proved to be unsuccessful as the pure compound had no cyclooxygenase inhibitory activity. It was subsequently determined that the compounds were lost during the HPLC procedure. An ethanolic extract of the bark of E. Iysistemon was purified in an attempt to isolate an anti-bacterial compound(s). Vacuum liquid chromatography and separation using the chromatotron was used to purify the crude extract. The more sensitive microtitre bioassay was used to test for anti-bacterial activity against S. aureus. The isoflavone, Wighteone was isolated. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2000.

The herbal medicine trade is thriving in KwaZulu Natal with an ever-increasing number of people harvesting and trading in indigenous plants, especially those species with medicinal and/or magical properties. The number of plants harvested has increased whereas the size of the plants collected has decreased, resulting in low recruitment into wild populations. As a result of these two factors, species diversity has decreased. To this end, the aim of these investigations was to establish micropropagation protocols for the selected species i.e. Bowiea volubilis, Haworthia_ limifolia and Cryptocarya latifolia. In addition, hardening-off protocols were also developed. The bulbous plant, Bowiea volubilis, was propagated via organogenesis using the inflorescence stem. Bulblet formation occurred directly without an intervening callus phase. Bulblets were produced on explants on Linsmaier and Skoog (1965) (LS) medium containing 30 g.r' sucrose and either I mg.r' BAP and I mg.r' 2,4-D or 1 mg.r' BAP and 1 mg.r' NAA. Shoots and roots were induced upon transfer to the basal medium devoid of plant growth regulators. Regenerated plantlets were successfully hardened-off. Haworthia limifolia, a succulent, was propagated via direct somatic embryogenesis using leaf material. Embryo formation was induced on a modified Murashige and Skoog (1962) (MS) medium containing 20 g.r' sucrose and 1 - 5 mg.r' 2,4-D. secondary embryogenesis occurred when the explants were transferred to the basal medium supplemented with activated charcoal and devoid of growth hormones. Healthy plantlets, produced from secondary embryos, were transferred to pots and acclimatised to greenhouse conditions. A large proportion of the plantlets regenerated were vitrified and as a result, this problem was addressed by changing the medium composition or culture environment. Silica gel, when placed in the culture vessel, was the best treatment for reversal of the vitrified condition. The establishment of leaf and nodal segment cultures of Cryptocarya latifolia required extensive investigation of sterilants to reduce fungal contamination. Several fungicides were tested and a successful sterilisation protocol was established. A number of media were tested for the induction of dormant axillary buds and multiplication of shoots. The best medium for both bud induction and proliferation was MS medium containing 30 g.r1 sucrose and 1 mg.r1 BAP and 0.01 mg.r1 NAA. Callus cultures were established on MS medium containing 30 g.r1 sucrose and 3 mg.rl 2,4-D. These calli, however, were non-embryogenic. Application of the established protocols and future research strategies are discussed. / Thesis (M.Sc.)-University of Natal, 1995.

Due to over-exploitation of commonly-used medicinal plants, mainly from KwaZuluNatal, because of ever-increasing human population growth, many of the useful medicinal plants are becoming depleted in their natural habitats. Some species like Warburgia salutaris, which is currently declared very rare in the KwaZulu-Natal province, appear to be on the verge of extinction. In order to counteract this overexploitation, this study sought to provide information that could help resource users to grow these threatened species through ex situ conservation methods. A short list of heavily utilised medicinal tree specles was selected from the approximately 700 tree species indigenous to KwaZulu/Natal. The criteria considered for short listing were; life form, species scarcity, past population status and part used. A total of 23 species were short listed, but a subset of 12 species was selected based on the availability of fruits and seeds. The aim of short-listing was to work on a manageable number of commonly utilised medicinal tree species. The seed physiology and growth of these species were studied. With the exception of Erythrophleum lasianthum and Curtisia dentata, all of them had a moisture content of 2': 20 % (on a dry mass basis), which is indicative of a recalcitrant behaviour. However, it could not be concluded that these seeds were truly recalcitrant because desiccation sensitivity was not directly assessed. Using the triphenyl tetrazolium chloride (TTC) viability test, most of the seeds of the 12 species seemed to be of good quality. Results of the TTC test for seed viability were similar to results obtained v using direct germination for most species. Results of flotation test for seed viability were different from the results obtained using direct germination for most spcies. The pre-treatment which achieved the highest germination percentage in almost all the seed types was cracking the outer coverings. Cracking pre-treatment appeared to be efficient in enhancing the removal of some substances which might inhibit germination of seeds. Hot water and acid pre-treatments frequently reduced germination. Growth of young seedlings was assessed in terms of stem diameter, height, and leaf area under sun and shade. Seedling growth in terms of stem diameter and height of most species did not show any significant difference. One of the few species which showed statistically significant differences in stem diameter growth was Ekebergia capensis. It was found that 3 out of lO of the species showed statistically significant differences in height growth. Two of the statistically significant differences in height occured on seedlings in the sun while one had statistically significant difference in the 40% shadecloth while 7 did not. Significant differences in leaf area occured on 7 out of lO species. Of these, 4 species had higher growth in the shade than in the sun while 3 had higher growth in the sun than in the shade. Generally, it appears that young developing seedlings establish themselves well under shade environment; this could be because most of the species used in this study are forest species. / Thesis (M.Sc.)-University of Natal, 1996.